Re: Hall of shame....
This is what I saw when I first came to the customers' house. They called me with questions about how the contractor was doing the shower pan liner, and from what they told me over the phone I knew it was going to be a good one.:yikes:
The homeowners used the shower twice, and then the shower floor started to come out. The installers had used mastic to set river rock sheet mounted stones. Rather than having a bed of mortar to form the sloping shower floor, they had just layered what they said was pool cement (which I think means they used this stuff the pool plasterers use), which was ~1/2" at the perimeter and down to 0" at the drain. In the photo you can see the whitish stain from the pool cement. It turns out that the pool cement was the only portland cement product they used in this bathroom.
The drain was not a standard three-piece clamping drain, but instead they had just used a floor drain like could be used on a patio or in a basement. They cut the pan liner around the perimter of the drain, and "sealed" it to the edge of the drain with latex painters caulk.
There was no sloping surface under the pan liner, and in fact parts of the liner were lower than the drain, so water collected in the liner and never made it to the drain.